Thursday, 9 February 2012
Third-winter Caspian Gull, 8th Feb
Two Caspian Gulls at Dogsthorpe in a quick look this morning included one of yesterday's first-winters and new third-winter. I initially assumed this was yesterday's fourth-winter, but there are clearly several differences (e.g. bill structure and pattern, primaries etc).
I must say I find ageing third/fourth-winter Casps difficult at times (guess it isn't reliably done in some birds). However, I'm pretty confident both yesterday's and Saturday's birds are 4w birds and today's a 3w. In addition to the primaries, there is quite alot of 'muck' in the upperwing coverts (and some brown on the fringes of the underwing coverts). Today's bird also seemed to show a tiny bit of black on the central tail feathers.
So, that's eight Caspian Gulls at The Dog since Saturday - two adults, two 4th-w, a 3rd-w and three 1st-w. Amazing stuff: all credit to weather conditions.